Lead frames are generally used in various types of integrated circuit (IC) packages. Different types of IC packages that incorporate a lead frame include, among others, quad flat packages (QFPs), quad flat no-lead (QFN) packages, etc. In most, if not all, of these IC packages, the lead frame acts as a mechanical support structure for the IC or die.
A lead frame typically includes a die attach paddle, leads and tie bars. The die attach paddle, held in place by the tie bars, is an area on the lead frame where the IC or die is placed. The leads connect the IC in the IC package to external circuit elements. Typically, wires are used to connect the IC on the die attach paddle to the leads. Some of the leads may be tied to a high voltage level, e.g., a positive voltage level, while others may be tied to a low voltage level, e.g., a ground potential.
Depending on the resources available, e.g., input/output (I/O) pins, on the IC, the leads may be arranged differently. As such, different lead frame designs may be required, depending on the resources available on the design of the IC. Generally speaking, the tie bars that hold the die attach paddle in place take up a certain amount of space at each of the corners of the lead frame. Therefore, the leads typically have to be arranged at a certain angle and there needs to be adequate spacing between the leads and the tie bars. Longer wires may need to be used to connect the IC on the die attach paddle to some of the leads at each corner of the lead frame.
It is desirable therefore to have a more uniform lead frame design that can accommodate different ICs. It is also desirable to have a lead frame without tie bars that occupy a substantially large area at each of the corners of the lead frame. It is within this context that the invention arises.